Hypopigmented patches are seen in

Nevus anemicus presents as a single or multiple patches of hypopigmentation with ill-defined margins merging into normal skin present at bih or thereafter. Nevus anemicus presents as congenital hypopigmented patches with a well-defined border. They are asymptomatic and typically seen on the upper trunk, although they have also repoed on the face and extremities. The distribution of hair, formation of sweat, and skin sensation are unaffected by nevus anemicus (Ref: harrison.20th edition pg 1267